Traditionally, a thrust reverser with grids comprises two half-cowlings mounted each sliding on a half-beam mounted pivoting on a nacelle-holding mast.
The sliding movement of each half-cowling on its associated half-beam makes it possible to make the thrust reverser go from a direct jet configuration to a reverse jet configuration, and vice versa.
The rotational movement of each half-beam on the nacelle-holding mast makes it possible to make each half-cowling pivot relative to said mast for maintenance operations.
As illustrated in the appended FIGS. 1 and 2, each half-beam 1 is formed in a ribbed metal alloy 3, and typically comprises, on its outer face, primary 5 and secondary 7 rails capable of allowing the movement of the associated half-cowling (not shown), and a plurality of hinge yokes 9a, 9b, 9c, 9d capable of allowing the articulation of the half-beam 1 on the associated nacelle mast.
A receptacle 11, mounted on the upstream part (relative to the direction of air flow in the nacelle) of the half-beam 1, allows the fixing of a front frame designed to support the grids of the thrust reverser (frame and grids not shown).
As visible in FIG. 3, the half-beam 1 is attached by riveting 13 on the upper part 15 of an internal fixed half-structure panel 17, generally made of a composite material, and defining, with the associated thrust reverser cowling, the cold air jet.
The assembly formed by the half-beam 1, its rails 5, 7 and its hinge yokes 9a to 9d is often referred to as “twelve-hour structure”, given its position at the top of the circle defined by a nacelle section, and by analogy with the dial of a watch.